It's so hard to differentiate between yellow card dissent and red card abuse just from the words said, you have to take into consideration a load more other factors eg what's happened up to that point in the game (other cards, dissent, style of match), who said it (what's he been like to you up to that point), how it was said (distance, volume, vitriol!), how you feel at the time (under pressure, "short fuse"). Personally just from the words used I would have given a caution for dissent, but that's me. We all have different tolerance levels, but we should be consistent in our application of law when specific words are used.